Despite its well-documented effects as a hormone disruptor, Bisphenol A (BPA) is still used to manufacture thousands of products ranging from cigarette filters to food packaging, medical devices and toys. BPA is used to create plastic coatings and harden clear plastics, but the compound mimics estrogen, potentially interfering with a growing child's hormones or contributing to the development of hormone-dependent diseases.
In the last decade, consumer pressure and government regulations have helped phase out the addition of BPA to plastic baby and water bottles. Yet, the chemical is so ubiquitous, recent population exposure studies suggest that just about every person living in an industrialized nation absorbs minuscule amounts of BPA every day, mostly through food. Scientists still don't know if this chronic, extremely low-level exposure has any ill-effects.
"The body is very efficient at excreting BPA in urine within just a few hours, and exposures are generally orders of magnitude below safety limits set by governments," says Liesel Seryak, PhD, an environmental health scientist who was a post-doctoral researcher at The Ohio State University College of Public Health. "However, we don't have a lot of information about certain populations that might have greater exposure because their occupation requires them to handle objects containing BPA."
Supported by resources from Ohio State's Center for Clinical and Translational Science (CCTS), Seryak and the study's principal investigator, Jay Wilkins, DrPH, have zeroed in on one high-risk population: cashiers. Regular handling of thermal printed receipts, which are coated with BPA, may increase their exposure. People in banking, service and travel industries who frequently come in contact with printed tickets or receipts are also potentially at risk for elevated BPA exposure.
"Previous studies have estimated that a cashier working for 10 hours a day handling BPA-coated receipts could be exposed to higher amounts of BPA than the average person, but there have been very few controlled studies done to get an actual measurement of exposure," says Seryak. "With more than 3.3 million cashiers working in the US, it's a really interesting population to get a baseline reading on."
Eliminating BPA from the Diet
The study was conducted in two parts: one observational, one experimental. Wilkins' team used the volunteer database, ResearchMatch, as well as paper flyers, advertisements and social networks to recruit 31 local participants (25 cashiers and 6 non-cashiers). In the observational part of the study, the 25 cashiers had their BPA exposure measured in urine samples before and after one regular shift at their job. The 6 non-cashiers participated in the experimental portion, undergoing a single 22-hour monitoring of BPA exposure before, during and after handling receipts in a controlled clinical environment.
In order to get a valid measurement on BPA exposure, the researchers had to eliminate as much BPA from the study participants' environment as possible. Since most BPA is ingested, Seryak turned to clinical research dietitian Sarah Rusnak for a solution.
"We knew that preparing the meals in our kitchen would be essential for reducing BPA exposure. But we found it was extremely difficult to find foods, food packaging and cooking utensils that didn't contain BPA," said Rusnak, MS, RD, LD with Ohio State's Clinical Research Center.
After contacting several manufacturers and food companies regarding ingredients and packaging options, Rusnak's team was able to assemble several BPA-packaging-free meals for the study participants using BPA-free kitchen utensils. These included stainless steel ice cube trays, BPA-free lunch boxes and ice packs, and a glass French press for coffee. Published literature shows that BPA can be found in napkins, brown paper bags and cardboard boxes, so the research team avoided using foods that had come in contact with any of those items.
"Clearly in this day and age, avoiding BPA entirely is impossible, and I can't imagine a life without plastics. However, with some research, consumers can find ways to reduce BPA exposure in their diets," said Rusnak, who also is member of Ohio State's Food Innovation Center.
BPA Use Reducing, but Issues Remain
Currently, Wilkins' team is analyzing the data, and hopes to publish their findings within a few months. Early results show that the steps the team took to control dietary exposure of BPA were successful. The results also indicate that fewer and fewer companies appear to be using BPA-coated receipts. However, Seryak isn't convinced this is a good trend.
"People should realize that BPA-free doesn't mean chemical free. Now, many manufacturers are using BPS instead -- and it's also a hormone disruptor," said Seryak. "Research cannot keep up with how fast technology and consumer sentiment changes. We could be trading out one perceived problem for another."
Seryak says that it can be difficult to know if receipts or tickets are BPA-coated; if workers are concerned about their personal exposure, they could likely reduce it by wearing disposable gloves or washing hands on breaks.
Seryak has been studying environmental exposure to endocrine disrupters and women's health for 10 years, and has focused her research on sources and routes of BPA exposure most recently. The study was primarily funded by a grant(#1R21OH010332-01) from The National Institute for Occupational Safety and Health with support from the CCTS.
Materials provided by Ohio State University Center for Clinical and Translational Science. Note: Content may be edited for style and length.
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